In the selector of this patent, the raising of each drawbar, at the time of its selection, is ensured by an individual control by electromagnet. Each drawbar comprises an extension below which is located an electromagnet whose movable core causes raising of the drawbar when the electromagnet is excited.
This solution requires not only electromagnets, but also miniature contact breakers, relays, connecting wires etc. If thus leads to a certain complexity of construction, hence a relatively high cost price, insufficient reliability and it is difficult to maintain, since experts in this field are more familiar with mechanical devices than with electrical systems.
To remedy these drawbacks and in particular the last drawback mentioned above, it is particularly advantageous to provide a purely mechanical solution. However, completely mechanical weft thread selectors as used at present are themselves quite complex. In fact, the control of thread guides in the latter is generally achieved from the movements of the dobby levers, by by means of an arrangement of cables, the number of which is equal to the number of thread guides. Furthermore, the selection of each thread guide and the possible locking operations are also ensured by individual means, i.e. means which have to be multiplied by four for example in the case of a loom with weft threads of four different colors.